Part 2 of Reversal of aging and immunosenescent trends with sulforaphane

Reversal of aging and immunosenescent trends with sulforaphane covered only the first 13 minutes of a super informative presentation by the lead researcher of clinical trial Reversal of aging and immunosenescent trends.  Commonalities with sulforaphane research were found by PubMed searches of sulforaphane and each presentation topic, and used a 1/1/2015 publication date cutoff.

Continuing presentation topics from the 13:40 mark:

Cancer

Lymphocyte/monocyte ratio

CD38 monocytes

  • NQO1-induced activation of AMPK contributes to cancer cell death by oxygen-glucose deprivation

    “NQO1 plays a key role in AMPK-induced cancer cell death in OGD through the CD38/cADPR/RyR/Ca2+/CaMKII signaling pathway. Expression of NQO1 is elevated by hypoxia/reoxygenation or inflammatory stresses through nuclear accumulation of the NQO1 transcription factor, Nrf2 (NFE2-related factor 2). Activation of the cytoprotective Nrf2 antioxidant pathway by sulforaphane protects immature neurons and astrocytes from death caused by exposure to combined hypoxia and glucose deprivation.”

Thymus – no recent sulforaphane studies

Renal function

  • Rapid and Sustainable Detoxication of Airborne Pollutants by Broccoli Sprout Beverage: Results of a Randomized Clinical Trial in China

    “Rapid and sustained, statistically significant increases in levels of excretion of glutathione-derived conjugates of benzene (61%), acrolein (23%), but not crotonaldehyde were found in those receiving broccoli sprout beverage compared with placebo. Excretion of benzene-derived mercapturic acid was higher in participants who were GSTT1-positive compared to the null genotype, irrespective of study arm assignment. Measures of sulforaphane metabolites in urine indicated that bioavailability did not decline over the 12-week daily dosing period. Intervention with broccoli sprouts enhances detoxication of some airborne pollutants, and may provide a frugal means to attenuate their associated long-term health risks.”

Hair rejuvenation

Epigenetic clocks – There are no sulforaphane studies that use epigenetic clocks, although broccoli compounds have epigenetic effects on aging, as reviewed in 2019:

  • Sulforaphane – role in aging and neurodegeneration

    “SFN has been shown to modulate several cellular pathways in order to activate diverse protective responses, which might allow avoiding cancer and neurodegeneration as well as improving cellular lifespan and health span.”


Both biomarker (Lymphocyte / monocyte ratio) and epigenetic clock (GrimAge) measurements done 6 months after the clinical trial ended suggested trial subjects’ aging phenotypes had been reset:

An environmental signaling paradigm of aging explained:

“Apart from being slowed down or sped up, the body clock can also be reset. Organisms, organs, and their cells can be reset to different age-phenotypes depending on their environment.

This is not so much a principle as an application of principle that the environment determines age-phenotype.”

There wouldn’t be a potential payoff for a company to study any broccoli compound / aging connections. People can achieve clinically relevant, daily doses of broccoli sprouts for < $500 a year.

What sponsor would be interested enough to put sulforaphane research on the clock?

Presentation topics are continued in Uses of the lymphocytes to monocytes ratio and A review of sulforaphane and aging. This pilot trial’s follow-on clinical trial was updated in The next phase of reversing aging and immunosenescent trends.

Reevaluate findings in another paradigm

It’s challenging for people to change their framework when their paychecks or mental state or reputations depend on it not changing.

I’ll use The hypothalamus and aging as an example. This review was alright for partial fact-finding up through 2018. Its facts were limited, however, to what fit into the reviewers’ paradigm.

The 2015 An environmental signaling paradigm of aging provided examples of findings that weren’t considered in this 2018 review. It also presented a framework that better incorporated what was known in 2015.


Here’s how they viewed the same 2013 study, Hypothalamic programming of systemic ageing involving IKK-β, NF-κB and GnRH (not freely available).

Paradigm: “The hypothalamus is hypothesized to be a primary regulator of the process of aging of the entire body.”

Study assessment:

“Age-associated inflammation increase is mediated by IκB kinase-β (IKK-β) and nuclear factor κB (NF-κB) in microglia and, subsequently, nearby neurons through microglia–neuron interaction in the mediobasal hypothalamus. Apparently, blocking hypothalamic or brain IKK-β or NF-κB activation causes delayed aging phenotype and improved lifespan.

Aging correlates with a decline in hypothalamic gonadotropin-releasing hormone (GnRH) expression in mice. Mechanistically, activated IKK-β and NF-κB significantly down-regulates GnRH transcription. GnRH therapy through either hypothalamic third ventricularor or subcutaneous injection leads to a significant recovery of neurogenesis in the hypothalamus and hippocampus, and a noticeable improvement of age-related phenotype in skin thickness, bone density, and muscle strength when applied in middle-aged mice.”


Paradigm: Environmental signaling model of aging

Study assessment:

“A link between inflammation and aging is the finding that inflammatory and stress responses activate NF-κB in the hypothalamus and induce a signaling pathway that reduces production of GnRH by neurons. GnRH decline contributes to aging-related changes such as bone fragility, muscle weakness, skin atrophy, and reduced neurogenesis. Consistent with this, GnRH treatment prevents aging-impaired neurogenesis, and decelerates aging in mice.

Zhang et al. report that there is an age-associated activation of NF-κB and IKK-β. Loss of sirtuins may contribute both to inflammation and other aspects of aging. But this explanation, also given by Zhang et al., merely moves the question to why there is a loss of sirtuins.

The case is particularly interesting when we realize that the aging phenotype can only be maintained by continuous activation of NF-κB – a product of which is production of TNF-α.

Reciprocally, when TNF-α is secreted into the inter-cellular milieu, it causes activation of NF-κB. In their study, Zhang et al. noted that activation of NF-κB began in microglia (the immune system component cells found in the brain), which secreted TNF-α, resulting in a positive feedback loop that eventually encompassed the entire central hypothalamus.

The net result of this is a diminution in production of gonadotropin-releasing factor which accounted for a shorter lifespan. Provision of GnRH eliminated that effect, while either preventing NF-κB activation (or that of the IKK-β upstream activator) or by providing gonadotropin-releasing factor directly into the brain, or peripherally, extending lifespan by about 20%.

In spite of the claim of Zhang et al. that the hypothalamus is the regulator of lifespan in mice, their experiments show that only some aspects of lifespan are controlled by the hypothalamus, as preventing NF-κB activation in this organ did not stop aging and death. Similar increased NF-κB activation with age has been seen in other tissues as well, and said to account for dysfunction in aging adrenal glands.

It was demonstrated that increased aging occurred as a result of lack of gonadotropin-releasing hormone, and that increased lifespan resulted from its provision during aging. In this manner:

  1. Aging of hypothalamic microglia leads to
  2. Aging of the hypothalamus, which leads to
  3. Aging elsewhere in the body.

So here we have a multi-level interaction:

  1. Activation of NF-κB leads to
  2. Cellular aging, leading to
  3. Diminished production of GnRH, which then
  4. Acts (through cells with a receptor for it, or indirectly as a result of changes to GnRH-receptor-possessing cells) to decrease lifespan.

So the age state of hypothalamic cells, at least with respect to NF-κB activation, is communicated to other cells via the reduced output of GnRH.”


Not using the same frameworks, are they?

In 2015, this researcher told the world what could be done to dramatically change the entire aging research area. He and other researchers did so recently as curated in Part 3 of Rejuvenation therapy and sulforaphane which addressed hypothalamus rejuvenation.

Part 3 of Rejuvenation therapy and sulforaphane

Part 1 focused on the study’s clinical biomarkers. Part 2 highlighted its epigenetic clocks. Now we’ll look at rejuvenation of cognitive function.

Charts for this study’s most relevant human aging applications – measured by the new human-rat relative biological age clock – were in supplementary data due to combining study untreated tissue samples into clock training data. Reanalyses showed:

“Using the final version of the epigenetic clocks, we find that treatment effects become even more significant especially for the hypothalamus.”

Human-rat relative clock percentages of rejuvenation were:

  • “Blood 70.6%
  • Liver 79.4%
  • Heart 61.6%
  • Hypothalamus 20.9%”

The Discussion section addressed hypothalamus rejuvenation:

“Why does plasma fraction treatment not reduce brain epigenetic age by the same magnitude as it does other organs? We can only begin to address this question after having first understood what epigenetic aging entails.

As it stands, our knowledge in this area remains limited, but it is nevertheless clear that:

  1. Epigenetic aging is distinct from the process of cellular senescence and telomere attrition,
  2. Several types of tissue stem cells are epigenetically younger than non-stem cells of the same tissue,
  3. A considerable number of age-related methylation sites, including some clock CpGs, are proximal to genes whose proteins are involved in the process of development,
  4. Epigenetic clocks are associated with developmental timing, and
  5. Relate to an epigenomic maintenance system.

Collectively, these features indicate that epigenetic aging is intimately associated with the process of development and homeostatic maintenance of the body post-maturity.

  • While most organs of the body turnover during the lifetime of the host, albeit at different rates, the brain appears at best to do this at a very much slower rate.
  • While most tissues harbor stem cells that are necessary for replenishment and turnover, stem cells in adult brain have only been detected in a defined and very limited area of the subventricular zone, olfactory bulb (in rats), hippocampus and hypothalamic proliferative region.

As such, if plasma fraction treatment’s rejuvenating effect is:

  • Mediated through the process of development and
  • Involves tissue stem cells

then its effect on epigenetic age of the brain would appear to be modest, which indeed it does.

It is to be noted however, that improving brain function does not depend on neurogenesis as much as it does on synapse formation and factors such as NMDA receptors, which decline in density with age.

Assessment of plasma fraction treatment on cognitive function (learning and memory). Rats were subjected to Barnes maze test – nine consecutive days of test where the time (in seconds) required by rats to find the escape hole (latency) was recorded and plotted. Error bars depict 2 standard errors.

Within a month of plasma fraction treatment, rats exhibited significantly reduced latency to escape, i.e., they learned and remembered better. After the second month, treated rats began with a slightly reduced latency period compared to untreated old rats, and once again, they learned much faster than the latter.

By the third month, it was clear that treated rats remembered the maze much better than untreated ones even from the first day of test as their latency period was significantly reduced. By the end of the test period, their latency was similar to that of young rats. This feature was sustained and repeated in the fourth month.”

Not sure why there’s a 62-day gap between “Second month” and “Third month.” Maybe it had something to do with “First month” starting 10 days after the first treatment and “Third month” similarly starting 13 days after the second treatment?


Many of us know older people who lived well past their time of good cognitive function:

  • We see how they’re helpless and dependent; and
  • We see how others take advantage of them in their morbidity phase, where healthspan stops increasing but lifespan continues.

We can make personal plans for that day, sure. But let’s also put some urgency into applying this study’s new human-rat relative biological age clock, and make:

“A step change in aging research. Although conservation of aging mechanism could be equally deduced from the existence of multiple individual clocks for other mammals (mouse, dog), the single formula of the human-rat clock that is equally applicable to both species effectively demonstrates this fact.”

Part 2 of Rejuvenation therapy and sulforaphane

A rejuvenation therapy and sulforaphane focused on the study’s clinical biomarkers and not its biological age measurements. This Part 2 curation of the study highlights its epigenetic clocks because:

“While clinical biomarkers have obvious advantages (being indicative of organ dysfunction or disease), they are neither sufficiently mechanistic nor proximal to fundamental mechanisms of aging to serve as indicators of them. It has long been recognized that epigenetic changes are one of several primary hallmarks of aging.

DNA methylation (DNAm) epigenetic clocks capture aspects of biological age. The discrepancy between DNAm age and chronological age (term as ‘epigenetic age acceleration’) is predictive of all-cause mortality. Pathologies and conditions that are associated with epigenetic age acceleration includes, but are not limited to, cognitive and physical functioning, centenarian status, Down syndrome, HIV infection, obesity, and early menopause.

The [new] human-rat clocks apply to both species. The two human-rat pan-tissue clocks are distinct, by way of measurement parameters. One estimates absolute age (in units of years), while the other estimates relative age, which is the ratio of chronological age to maximum lifespan; with values between 0 and 1. This ratio allows alignment and biologically meaningful comparison between species with very different lifespan (rat and human), which is not afforded by mere measurement of absolute age.

Relative age estimation was made using the formula: Relative age = Age / maxLifespan where the maximum lifespan for rats and humans were set to 3.8 years and 122.5 years, respectively.”

From Supplementary Table 3, old control and old treatment subjects were males 109 weeks old, 55% of their maximum lifespan (109 / 197.6). Young control subjects were males 30 weeks old, 15% of their maximum lifespan.

The money charts for this study’s human aging applications – measured by the new human-rat relative biological age clock – were buried in Supplementary Figure 12, bar plots M through P:

“Human-rat clock measure of relative age defined as age/maximum species lifespan. Each bar-plot reports the mean value and one standard error.”

From Supplementary Table 8, the percentages of rejuvenation for the above bar plots, calculated as “(100 * (1 – Old Treated / Old Control)” were:

  • “Blood 70.6%
  • Liver 79.4%
  • Heart 61.6%
  • Hypothalamus 20.9%”

Let’s return to clinical biomarkers for comparison purposes. The current study measured pro-inflammatory cytokine IL-6 blood plasma levels at every time point, but didn’t publish numbers. Bar plots and narrative were:

“Inflammation is an important response that helps protect the body, but excess inflammation especially in terms of duration of this response can have very detrimental effects instead. This occurs when inflammation fails to subside and persists indefinitely; a condition referred to as chronic inflammation, which for reasons not well-understood, increases with age and is associated with a multitude of conditions and pathologies.

The levels of two of the most reliable and common biomarkers of chronic inflammation, interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α), are found to be considerably higher in old rats, and these were very rapidly diminished, within days by plasma fraction treatment, to comparable levels with those of young rats. This was especially stark with IL-6.

In time, the levels of these inflammatory factors began to rise gradually, but they were once again very effectively reduced following the second administration of the plasma fraction on the 95th day.”

Let’s compare the above IL-6 graphic with IL-6 concentration improvements of our 2018 model clinical trial, Effects of long-term consumption of broccoli sprouts on inflammatory markers in overweight subjects, calculated as (100 * (1 – Day _ mean / Day 0 mean):

Mean pg/ml | % improvement | Period | Broccoli sprout consumption

  • 4.594 | 0% | Day 0 | “One week before the beginning of the intervention period, subjects were asked to avoid the consumption of Brassica vegetables (broccoli, radish, cauliflower, Brussel sprouts, mustards, among others) and their derived products.”
  • 1.748 | 62.0% | Day 0 to 70 | Subjects ate 30 g raw broccoli sprouts every day, and stopped eating them after Day 70.
  • 0.896 | 80.5% | Day 0 to 90 | “After the intervention period, a follow-up recovery period for all subjects continued for another 90 days with no ingestion of broccoli sprouts.”
  • 2.170 | 52.8% | Day 0 to 160 | Subjects had not eaten broccoli sprouts after Day 70.

Results between the studies were similar in that:

  1. IL-6 levels improved during early treatments through rat Day 8 and human Day 70, respectively.
  2. IL-6 levels continued decreasing shortly after treatments for 7 days (through rat Day 15) and 20 days (through human Day 90), respectively.
  3. IL-6 levels rose after rat Day 15 and human Day 90, respectively, but were still significantly below Day 0 values at rat Day 95 and human Day 160.

The current study measured Nrf2 but didn’t publish numbers. Bar plots and narrative were:

“The reduction of these inflammation markers is consistent with the profile of the nuclear factor erythroid 2-like 2 protein (Nrf2), which plays a major role in resolving inflammation, in part by inhibiting the expression of IL-6 and TNF-α. Nrf2 also induces the expression of antioxidants that neutralizes ROS [reactive oxygen species], which is also a significant feature in inflammation.”

A PubMed search on “nrf2 sulforaphane human” didn’t turn up relevant 2020 human in vivo studies. I disregarded reviews, cancer studies, disproven hypotheses, and other compounds listed in the below graphic.

I won’t repeat the entire Nrf2 section from the Part 1 curation, just one graphic and paragraph:

It [sulforaphane] is not only a potent Nrf2 inducer but also highly bioavailable [around 80%], so that modest practical doses can produce significant clinical responses. Other Nrf2 activators [shown in the above image] not only lack potency but also lack the bioavailability to be considered as significant intracellular Nrf2 activators.”


As noted in Reviewing clinical trials of broccoli sprouts and their compounds, there are no sulforaphane clinical trials that also use epigenetic clocks. Broccoli sprouts and their compounds’ effects on human aging is an area that hasn’t drawn attention and funding.

What effects may broccoli sprout compounds have on human aging? With this new human-rat relative biological age clock, researchers can get reliable answers from rat studies, with human clinical trials needed only to confirm those findings!

As rejuvenation research continues, what could people do easily, cheaply, and today for our long-term selves? Don’t know about the hypothalamus, but our blood, liver, and heart biological ages may decrease as we reduce inflammation and oxidative stress by eating broccoli sprouts.

I’m at a similar percentage of species maximum lifespan as were the study’s treated subjects. It’s my choice as to what my healthspan will be.

There isn’t evidence today to definitively say that changing my inflammatory phenotype with broccoli sprouts has had / will have rejuvenation effects on biological ages of my cells, organs, and body. But if eating broccoli sprouts every day not only reduces chronic inflammation and oxidative stress as expected, but also makes me younger, I could probably learn to live with that. 🙂

Continued with Part 3 of Rejuvenation therapy and sulforaphane.

A rejuvenation therapy and sulforaphane

The founder of the epigenetic clock methodology with the coauthor of Aging as an unintended consequence released a 2020 rodent study “Reversing age: dual species measurement of epigenetic age with a single clock” at https://www.biorxiv.org/content/10.1101/2020.05.07.082917v1.full.pdf:

“We employed six clocks to investigate the rejuvenation effects of a plasma fraction treatment in different rat tissues. Two of these epigenetic clocks apply to both humans and rats.

The treatment more than halved the epigenetic ages of blood, heart, and liver tissue. A less pronounced, but statistically significant, rejuvenation effect could be observed in the hypothalamus.

The treatment was accompanied by progressive improvement in the function of these organs as ascertained through numerous biochemical/physiological biomarkers and behavioral responses to assess cognitive functions. Cellular senescence, which is not associated with epigenetic aging, was also considerably reduced in vital organs.

Plasma fraction treatment consists of two series of intravenous injections of plasma fraction. Rats were injected four times on alternate days for 8 days. A second identical series of injections were administered 95 days later. In its entirety, the experiment lasted 155 days.

Overall, this study demonstrates that a plasma-derived treatment markedly reverses aging according to epigenetic clocks and benchmark biomarkers of aging.”

The study hasn’t been peer reviewed, so can’t be viewed yet as conclusive. Given that researchers’ single-most valuable asset is their reputations, though, will the findings have major revisions?


I was alerted to the study by Josh Mitteldorf’s blog post Age Reduction Breakthrough, who did his usual excellent curation:

“Most of the explosion in aging research (and virtually all the venture capital startups) are looking to treat aging at the cellular level. Their paradigm is that aging is an accumulation of molecular damage, and they see their job as engineering of appropriate repair mechanisms.

The truth, as Katcher [the lead lab researcher] understands it, is that, to a large extent, aging is coordinated system-wide via signal molecules in the blood. The problem is that there are thousands of constituents represented in tiny concentrations in blood plasma, but conveying messages that cells read. Which of these are responsible for aging?

The two-species clock[s] was [were] a significant innovation, a first bridge for translating results from an animal model into their probable equivalent in humans. Besides the methylation clock[s], the paper presents evidence of rejuvenation by many other measures. For example:

  • IL-6, a marker of inflammation, was restored to low youthful levels;
  • Glutathione (GSH), superoxide dismutase (SOD), and other antioxidants were restored to higher youthful levels;
  • In tests of cognitive function (Barnes maze), treated rats scored better than old rats, but not as well as young rats.;
  • Blood triglycerides were brought down to youthful levels;
  • HDL cholesterol rose to youthful levels; and
  • Blood glucose fell toward youthful levels.

These results bring together three threads that have been gaining credibility over the last decade. Mutually reinforcing, the three have a strength that none of them could offer separately.

  1. The root cause of aging is epigenetic progression = changes in gene expression over a lifetime.
  2. Methylation patterns in nuclear DNA are not merely a marker of aging, but its primary source. Thus aging can be reversed by reprogramming DNA methylation.
  3. Information about the body’s age state is transmitted system-wide via signal molecules in the blood. Locally, tissues respond to these signals and adopt a young or an old cellular phenotype as they are directed.”

Several of these aging measurements are also positively affected by sulforaphane. Using Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease as a reference:

1. “Chronic inflammation”

“Antioxidants in general and glutathione in particular can be depleted rapidly under conditions of oxidative stress, and this can signal inflammatory pathways associated with NF-κB. SFN [sulforaphane] has been shown to inhibit NF-κB in endothelial cells.

Two key inflammatory cytokines were measured at four time points in forty healthy overweight people [our model clinical trial, Effects of long-term consumption of broccoli sprouts on inflammatory markers in overweight subjects]. The levels of both interleukin-6 (Il-6) and C-reactive protein (CRP) declined over the 70 days during which the sprouts were ingested. These biomarkers were measured again at day 90, wherein it was found that Il-6 continued to decline, whereas CRP climbed again. When the final measurement was taken at day 160, CRP, although climbing, had not returned to its baseline value. Il-6 remained significantly below the baseline level at day 160.”

OMCL2019-2716870.010

2. “Oxidative stress”

“As a mediator for amplification of the mammalian defence system against various stressors, Nrf2 [nuclear factor erythroid 2-related factor 2] sits at the interface between our prior understanding of oxidative stress and the endogenous mechanisms cells use to deal with it. Diseases known to be underpinned by oxidative stress are proving to be more responsive to amplification of cellular defences via Nrf2 activation than by administration of direct-acting antioxidant supplements.

SFN, with absolute bioavailability of around 80%, [is] capable of increasing several endogenous antioxidant compounds via the transcription factor, Nrf2.

Nrf2 is ubiquitously expressed with the highest concentrations (in descending order) in the kidney, muscle, lung, heart, liver, and brain. Nrf2 was shown to prevent endothelial cells from exhibiting a proinflammatory state. Nrf2 is required for protection against glucose-induced oxidative stress and cardiomyopathy in the heart.

Well in excess of 500 genes have been identified as being activated by SFN via the Nrf2/ARE [Antioxidant Response Element] pathway, and it is likely that this underestimates the number as others are being discovered. Of the available SFN clinical trials associated with genes induced via Nrf2 activation, many demonstrate a linear dose-response. More recently, it has become apparent that SFN can behave hormetically with different effects responsive to different doses.

It [sulforaphane] is not only a potent Nrf2 inducer but also highly bioavailable so that modest practical doses can produce significant clinical responses. Other Nrf2 activators [shown in the above image] not only lack potency but also lack the bioavailability to be considered as significant intracellular Nrf2 activators.”


The study’s most relentlessly questioned, scrutinized, and criticized findings may be the two new epigenetic clocks that apply to both humans and rats. The researchers invited other researchers to validate these clocks because:

“If validated, this would be a step change in aging research. Although conservation of aging mechanism could be equally deduced from the existence of multiple individual clocks for other mammals (mouse, dog), the single formula of the human-rat clock that is equally applicable to both species effectively demonstrates this fact.”

The commonalities of this study with efforts to change my inflammatory phenotype with broccoli sprouts were summarized in the Discussion section:

“Apart from rejuvenating the vital organs of the treated rats, plasma fraction also impacted two fundamental physiological processes that underlie a great number of pathologies, namely oxidative stress and inflammation. Within a week of treatment, the markers of chronic inflammation (IL-6 and TNF-α) were significantly reduced and remained low throughout the entire experiment.

Likewise, markers of oxidative stress in brain, heart, lung and liver, which were very much higher in control old rats, were at the end of the experimental period, indistinguishable between plasma fraction-treated old rats and young ones. Concomitant with this drastic reduction in oxidative stress was the augmented levels of antioxidants (GSH, Catalase and SOD) in these tissues, indicating that modulating the levels of ROS [reactive oxygen species] to that of youthful rats is at least one way by which plasma fraction suppresses oxidative stress. It remains to be ascertained whether the rate of ROS generation is also reduced.

The levels of Nrf2, a transcription factor that impacts on oxidative stress, as well as inflammation, were raised by plasma fraction treatment of old rats to those of the young ones, indicating yet another level by which this treatment modulates these two critical processes. Collectively, these results show that plasma fraction treatment impacts not only the overt performances of organs, but also the underlying physiological processes that are pivotal for optimal organ function and health.”

Great stuff, huh? Are you ready to change your phenotype?

Continued with Part 2 of Rejuvenation therapy and sulforaphane.

Linear thinking about biological age clocks

This 2020 review by a Hong Kong company’s researchers compared and contrasted measures of biological age:

“More than a dozen aging clocks use molecular features to predict an organism’s age, each of them utilizing different data types and training procedures. We offer a detailed comparison of existing mouse and human aging clocks, discuss their technological limitations and the underlying machine learning algorithms. We also discuss promising future directions of research.

Biomarkers placed on an intuitive plane of Accuracy vs Utility. Bubble size depends on the number of clocks based on a corresponding aging biomarker.

Currently, DNAm [DNA methylation] is the most accurate and the most frequently used biomarker in biohorology. However, it is harder to apply a DNAm clock compared to clocks based on clinical blood tests. Moreover, DNAm marks often take a long time to emerge in response to aging interventions.

Chromatin structure and telomeres, while intriguing, are too labor intensive and error-prone to be practical.”

https://www.sciencedirect.com/science/article/pii/S1568163719302582 “Biohorology and biomarkers of aging: current state-of-the-art, challenges and opportunities”


We think about chronological age linearly. The reviewers hinted at but didn’t directly assess the extent to which techniques such as linear regression may also influence people to think linearly about biological age.

We experience cyclical changes every day (like sleep), month, season, and longer periods. The reviewers didn’t mention techniques that incorporate our cyclical experiences or assess cyclical biological age.

1. The reviewers pointed out some biological age clock linearity flaws:

“Most aging clocks base their BA [biological age] definitions either on CA [chronological age] or mortality risk. Mortality risk in its turn is derived from demographic tables and can be assumed to be a function of CA in most animals, including human.

Thus, aging clocks are ultimately treating CA as a substitute BA with the caveat that deviations from the actual CA signify better or worse physical fitness when compared to age matched controls. Such a design has several flaws.”

2. They pointed out non-linear characteristics of chromosomal telomere length:

“DNA lesions caused by oxidative stress are repaired less efficiently in telomeric regions, which causes frailty and subsequent telomere shortening. Oxidative stress levels may fluctuate due to habitat, life style, inflammatory diseases – factors that do not necessarily represent replicative clock ticking.

Telomere length typically fluctuates within ±2-4% per month. This led scientists to hypothesize that telomere attrition is an oscillatory process.”

Since cell components show cyclical phases, why wouldn’t cells and each higher living structural level likewise demonstrate cyclical phases? That avenue wasn’t explored.

3. They mentioned the non-linearity of epigenetic clocks:

“If an organism’s DNAm profile is not directly linked to the thermodynamic root of aging [entropy] but instead is a downstream product of competing processes, the applicability of DNAm aging clock methodology is at risk. In this case different aging clocks may not be equally good for different experiment settings.

While genetic, pharmacological and dietary interventions with proven effect on life expectancy change the methylation state of the age-associated CpG sites, they do so in different ways. Caloric restriction is more efficient in preventing methylation loss at hypomethylated sites and methylation gain at hypermethylated sites than rapamycin.

These findings imply that DNAm profiles do not simply gravitate towards the average with age and that there is no single pathway through which all aging processes are imbued into an organism’s epigenetic landscape.”

4. Genetic and epigenetic regulatory pathways were presented with linear thinking:

“Protein structures encapsulating DNA and regulating its accessibility (chromatin and histones) have also been shown to change with age. Moreover, DNAm machinery and histone modifications are interlinked and change throughout aging concordantly.

For example, DNA methyltransferases are attracted by the H3K36me mark. With aging it is less tightly regulated, and thus, more sporadic DNAm occurs, which ultimately translates to epigenetic clock ticking.”


An individual’s capability to regulate their own aging phenotype wasn’t addressed, only externally applied “aging interventions.” Diseases were considered chronological-“age-associated.”

Biological aging was neither viewed as a disease nor as an unintended consequence. If these researchers don’t grasp the foundations of their field of study, why do they work in the biological aging field? It isn’t just math.

  • Could this paper reflect one company’s desire to frame arguments in favor of the company’s offered solution?
  • Could this paper reflect a “chronological age is the cause” meme that satisfied organizational imperatives for sponsors like the Buck Institute for Research on Aging?
  • Or could it be that the reviewers had other paradigms?

What do you think?

Broccoli sprouts oppose effects of advanced glycation end products (AGEs)

This 2020 Australian/UK review subject was AGEs:

“AGEs are formed during cooking and food processing or produced endogenously as a consequence of metabolism. Deleterious effects of AGEs are underpinned by their ability to trigger mechanisms well known to elicit metabolic dysfunction, including activation of inflammatory pathways, oxidative stress and impaired mitochondrial oxidative metabolism. They have been widely implicated in complications of diabetes affecting cardiovascular health, the nervous system, eyes and kidneys.

Reactive carbonyl groups are constantly being produced via normal metabolism and when production overrides detoxification, AGEs accumulate. AGE formation may take several days or weeks to complete in the body.

Factors affecting AGE content of food depends on composition of protein, fat, and sugar and types of processing and cooking methods employed, predominantly on temperature and duration of preparation. Circulating free-AGEs concentrations are a good marker for dietary AGE intake while plasma protein-bound AGEs better represent endogenously produced AGEs.

Receptor for Advanced glycation end products (RAGE) signals via transcription factor NF-kB increasing gene expression of inflammatory mediators and production of ROS (reactive oxygen species).”

https://onlinelibrary.wiley.com/doi/abs/10.1002/mnfr.201900934 “The Role of Dietary Advanced Glycation End Products (AGEs) in Metabolic Dysfunction” (not freely available)


Let’s use the Australian 2019 Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease as a reference for how sulforaphane may counter effects of AGEs:

1. “Activation of inflammatory pathways”

“Antioxidants in general and glutathione in particular can be depleted rapidly under conditions of oxidative stress, and this can signal inflammatory pathways associated with NF-κB. SFN [sulforaphane] has been shown to inhibit NF-κB in endothelial cells.

Two key inflammatory cytokines were measured at four time points in forty healthy overweight people [our model clinical trial, Effects of long-term consumption of broccoli sprouts on inflammatory markers in overweight subjects]. Levels of both interleukin-6 (Il-6) and C-reactive protein (CRP) declined over the 70 days during which sprouts were ingested. These biomarkers were measured again at day 90, wherein it was found that Il-6 continued to decline, whereas CRP climbed again. When the final measurement was taken at day 160, CRP, although climbing, had not returned to its baseline value. Il-6 remained significantly below the baseline level at day 160.”

OMCL2019-2716870.010

2. “When production overrides detoxification”

“SFN significantly activates Nrf2 and as such has the potential to modulate the expression of genes associated with redox balance, inflammation, detoxification, and antimicrobial capacity, all key components of the upstream cellular defence processes.

Toxins presented to Phase 1 enzymes produce intermediate compounds which are sometimes more toxic to cells than the initial toxin. It is therefore important that Phase 2 is sufficiently active that intermediate products cannot accumulate in the cellular environment.

As a monofunctional inducer, SFN has been described as an ideal detoxifier, as its effect on Phase 1 is minimal compared with its significant activity on Phase 2.”

3. “Oxidative stress”

“As a mediator for amplification of the mammalian defence system against various stressors, Nrf2 sits at the interface between our prior understanding of oxidative stress and endogenous mechanisms cells use to deal with it. Diseases known to be underpinned by oxidative stress are proving to be more responsive to amplification of cellular defences via Nrf2 activation than by administration of direct-acting antioxidant supplements.

SFN, with absolute bioavailability of around 80%, is capable of increasing several endogenous antioxidant compounds via transcription factor Nrf2.”

4. “Complications of diabetes affecting cardiovascular health, the nervous system, eyes and kidneys”

“Nrf2 is ubiquitously expressed with highest concentrations (in descending order) in the kidney, muscle, lung, heart, liver, and brain. Nrf2 was shown to prevent endothelial cells from exhibiting a proinflammatory state. Nrf2 is required for protection against glucose-induced oxidative stress and cardiomyopathy in the heart.

Well in excess of 500 genes have been identified as being activated by SFN via the Nrf2/ARE [Antioxidant Response Element] pathway, and it is likely that this underestimates the number as others are being discovered. Of available SFN clinical trials associated with genes induced via Nrf2 activation, many demonstrate a linear dose-response. More recently, it has become apparent that SFN can behave hormetically with different effects responsive to different doses.

It [sulforaphane] is not only a potent Nrf2 inducer but also highly bioavailable so that modest practical doses can produce significant clinical responses. Other Nrf2 activators [shown in the above image] not only lack potency but also lack the bioavailability to be considered as significant intracellular Nrf2 activators.”


As mentioned in Changing an inflammatory phenotype with broccoli sprouts, per the above bolded part of section 3, I stopped taking N-acetyl-cysteine, the precursor to our endogenous antioxidant glutathione. I stopped taking curcumin last year due to no noticeable effects, probably because of its poor bioavailability. I may soon stop taking more vitamin E than the RDA, and β-carotene.

I changed my diet last summer to reduce AGEs, with mild effects. I expect stronger effects from also daily eating 60 grams of 3-day-old broccoli sprouts that yield 27 mg of sulforaphane after microwaving.

Growing a broccoli sprouts Victory Garden

To follow up How much sulforaphane is suitable for healthy people? I’ve started growing broccoli sprouts, and a “30 60 grams of fresh broccoli sprouts incorporated daily into the diet” [1] program. See Week 2 of Changing an inflammatory phenotype with broccoli sprouts for changes.

I loosely follow [2]‘s sprouting guidelines. One preparation difference is microwaving per [3]‘s findings as follows:

My current microwaving time for 60 grams of 3-day-old broccoli sprouts in 100 ml of water with a 1000 W microwave on full power is 35 seconds. The temperature gets up to 57°C. See Enhancing sulforaphane content for changes. I immediately dump the broccoli sprouts into a colander and spray with cold water to stop heating at the desired temperature.

The first batch of broccoli sprouts was a mild, cabbage-tasting side dish to the home-style chicken soup on page 238 of [4].

The a priori hypotheses:

    1. 30 grams of fresh broccoli sprouts will not have “51 mg (117 μmol)” of glucoraphanin [1] because they “Used the elicitor methyl jasmonate (MeJA) by priming the seeds as well as by spraying daily. MeJA at concentrations of 156 μM act as stressor in the plant and enhances the biosynthesis of the phytochemicals glucosinolates. Compared to control plants without MeJA treatment, the content of compounds as the aliphatic glucosinolate glucoraphanin was enhanced up to 70%.” 117 μmol / 1.70 = 69 μmol is the expected glucoraphanin amount in 30 grams weight of fresh broccoli sprouts. 69 x 2 = 138 μmol in 60 grams.
    2. One measurement [5] of how much sulforaphane is present in fresh broccoli sprouts before microwaving is 100 μmol / 111 g = .9 μmol / g. (.9 x 30 g) = 27 μmol is the expected sulforaphane amount in 30 grams of fresh broccoli sprouts. Changed assumption to 0 μmol sulforaphane due to 2013 Sulforaphane: translational research from laboratory bench to clinic “Broccoli sprouts are correctly described as releasing, generating, or yielding but not containing SFN [sulforaphane].”
    3. Last week a [3] coauthor agreed to make the data available to facilitate calculations. While I’m waiting… The study said the Figure 3 HL60 sulforaphane amount was 2.45 μmol / g. Eyeball estimate of the below Figure 3 control (raw broccoli florets) is a glucoraphanin amount of ~2.2 μmol / g. I assume that the broccoli florets and sprouts conversion would be the same at a 2.45 μmol / 2.2 μmol ≈ 1.11 ratio. I expect that microwaving the raw broccoli sprouts to 60°C will convert the 138 μmol of glucoraphanin to a 153 μmol amount of sulforaphane at this assumed 1.11 conversion ratio.
    4. The estimated sulforaphane weight per [6] would be (153 μmol / 5.64) = 27 mg which is comparable to clinical trial dosages listed in [7] and [8].
    5. I’ve been sitting around a lot since returning from Milano, Italy, on February 24, 2020, and probably weigh around 75 kg. The estimated dosage represents 153 μmol of sulforaphane / 75 kg = 2.04 μmol of sulforaphane / kg, compared to the 1.36 μmol of glucoraphanin / kg average of [1]. (The study provided the subjects’ mean weight in Table 1 as “85.8 ± 16.7 kg.” The average dosage per kg body weight was 117 μmol of glucoraphanin / 85.8 kg = 1.36 μmol of glucoraphanin / kg.)
    6. Don’t have a practical estimate of the amount of sulforaphane I metabolize from post-microwave glucoraphanin that would add to the calculated 153 μmol of sulforaphane. Both [7] and [8] cited a 2012 study that found: “Some conversion of GRN [glucoraphanin] to SFN can occur in response to metabolism by the gut microflora; however, the response is inefficient, having been shown to vary ‘from about 1% to more than 40% of the dose.’”
    7. Don’t have a practical estimate of the “internal dose” [8] that would result from 153+ μmol of sulforaphane.

I don’t have a laboratory in my kitchen 🙂 and won’t have quantified results. See Grow a broccoli sprouts Victory Garden today! for August 2020 practices.


References in order of citation:

[1] 2018 Effects of long-term consumption of broccoli sprouts on inflammatory markers in overweight subjects

[2] 2017 You Need Sulforaphane – How and Why to Grow Broccoli Sprouts

[3] 2020 Microwave cooking increases sulforaphane level in broccoli curated in Microwave broccoli to increase sulforaphane levels

fsn31493-fig-0003-m

[4] 2016 Dr. Vlassara’s AGE-Less Diet: How a Chemical in the Foods We Eat Promotes Disease, Obesity, and Aging and the Steps We Can Take to Stop It

[5] 2016 Effect of Broccoli Sprouts and Live Attenuated Influenza Virus on Peripheral Blood Natural Killer Cells: A Randomized, Double-Blind Study

[6] 2020 https://pubchem.ncbi.nlm.nih.gov/compound/sulforaphane lists sulforaphane’s molecular weight as 177.3 g / mol. A 1 mg weight of sulforaphane equals a 5.64 μmol sulforaphane amount (.001 / 177.3).

[7] 2019 Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease

[8] 2019 Broccoli or Sulforaphane: Is It the Source or Dose That Matters? Note that a coauthor didn’t disclose their business’ conflict of interest for an effectively promoted commercial product.

How much sulforaphane is suitable for healthy people?

This post compares and contrasts two perspectives on how much sulforaphane is suitable for healthy people. One perspective was an October 2019 review from John Hopkins researchers who specialize in sulforaphane clinical trials:

Broccoli or Sulforaphane: Is It the Source or Dose That Matters?

These researchers didn’t give a consumer-practical answer, so I’ve presented a concurrent commercial perspective to the same body of evidence via an October 2019 review from the Australian founder of a company that offers sulforaphane products:

Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease


1. Taste from a clinical trial perspective:

“Harsh taste (a.k.a. back-of-the-throat burning sensation) that is noticed by most people who consume higher doses of sulforaphane, must be acknowledged and anticipated by investigators. This is particularly so at higher limits of dosing with sulforaphane, and not so much of a concern when dosing with glucoraphanin, or even with glucoraphanin-plus-myrosinase.

Presence and/or enzymatic production of levels of sulforaphane in oral doses ranging above about 100 µmol, creates a burning taste that most consumers notice in the back of their throats rather than on the tongue. Higher doses of sulforaphane lead to an increased number of adverse event reports, primarily nausea, heartburn, or other gastrointestinal discomfort.”

Taste wasn’t mentioned in the commercial review. Adverse effects were mentioned in this context:

“Because SFN is derived from a commonly consumed vegetable, it is generally considered to lack adverse effects; safety of broccoli sprouts has been confirmed. However, use of a phytochemical in chemoprevention engages very different biochemical processes when using the same molecule in chemotherapy; biochemical behaviour of cancer cells and normal cells is very different.”

2. Commercial products from a clinical trial perspective:

“Using a dietary supplement formulation of glucoraphanin plus myrosinase (Avmacol®) in tablet form, we observed a median 20% bioavailability with greatly dampened inter-individual variability. Fahey et al. have observed approximately 35% bioavailability with this supplement in a different population.”

Avmacol appeared to be the John Hopkins product of choice, as it was mentioned 15 times in its clinical trials table. A further investigation of Avmacol showed that its supplier for broccoli extract, TrueBroc, was cofounded by a John Hopkins coauthor! Yet the review stated:

“The authors declare no conflict of interest.”

Please disclose easily discoverable ethical and commercial conflicts without prevarication. Other products were downgraded with statements such as:

“5 or 10 g/d of BroccoPhane powder (BSP), reported to be rich in SF, daily x 4 wks (we have assayed previously and found this not to be the case).”

They also disclaimed:

“We have indicated clinical studies in which label results have been used rather than making dose measurements prior to or during intervention.”

No commercial products – not even the author’s own company’s – were directly mentioned in a commercial perspective.

3. Dosage from a clinical trial perspective:

“Reporting of administered dose of glucoraphanin and/or sulforaphane is a poor measure of the bioavailable / bioactive dose of sulforaphane. As a consequence, we propose that the excreted amount of sulforaphane metabolites (sulforaphane + sulforaphane cysteine-glycine + sulforaphane cysteine + sulforaphane N-acetylcysteine) in urine over 24 h (2–3 half-lives), which is a measure of “internal dose”, provides a more revealing and likely consistent view of delivery of sulforaphane to study participants.

Only recently have there been attempts to define minimally effective doses in humans – an outcome made possible by development of consistently formulated, stable, bioavailable broccoli-derived preparations.”

Dosage from a commercial perspective:

“Of available SFN clinical trials associated with genes induced via Nrf2 activation, many demonstrate a linear dose-response. More recently, it has become apparent that SFN can behave hormetically with different effects responsive to different doses. This is in addition to its varying effects on different cell types and consequent to widely varying intracellular concentrations.

A 2017 clinical pilot study examined the effect of an oral dose of 100 μmol (17.3 mg) encapsulated SFN on GSH [reduced glutathione] induction in humans over 7 days. Pre- and postmeasurement of GSH in blood cells that included T cells, B cells, and NK cells showed an increase of 32%. Researchers found that in the pilot group of nine participants, age, sex, and race did not influence the outcome.

Clinical outcomes are achievable in conditions such as asthma with daily SFN doses of around 18 mg daily and from 27 to 40 mg in type 2 diabetes. The daily SFN dose found to achieve beneficial outcomes in most of the available clinical trials is around 20-40 mg.”

The author’s sulforaphane products are available in 100, 250, and 700 mg capsules of enzyme-active broccoli sprout powder.

4. Let’s see how these perspectives treated a 2018 Spanish clinical trial published as Effects of long-term consumption of broccoli sprouts on inflammatory markers in overweight subjects.

From a commercial perspective:

“In a recent study using 30 grams of fresh broccoli sprouts incorporated daily into diet, two key inflammatory cytokines were measured at four time points in forty healthy overweight [BMI 24.9 – 29.9] people. Levels of both interleukin-6 (Il-6) and C-reactive protein (CRP) declined over the 70 days during which sprouts were ingested.

These biomarkers were measured again at day 90, wherein it was found that Il-6 continued to decline, whereas CRP climbed again. When the final measurement was taken at day 160, CRP, although climbing, had not returned to its baseline value. Il-6 remained significantly below baseline level at day 160.

Sprouts contained approximately 51 mg (117 μmol) GRN [glucoraphanin], and plasma and urinary SFN metabolites were measured to confirm that SFN had been produced when sprouts were ingested.”


From a clinical trial perspective, glucoraphanin dosage was “1.67 (GR) μmol/kg BW.” This wasn’t accurate, however. It was assumed into existence by:

“In cases where authors did not indicate dosage in μmol/kg body weight (BW), we have made those calculations using a priori assumption of a 70 kg BW.”

117 μmol / 1.67 μmol/kg = 70 kg.

This study provided overweight subjects’ mean weight in its Table 1 as “85.8 ± 16.7 kg.” So its actual average glucoraphanin dosage per kg body weight was 117 μmol / 85.8 kg = 1.36 μmol/kg. Was making an accurate calculation too difficult?

A clinical trial perspective included this study in Section “3.2. Clinical Studies with Broccoli-Based Preparations: Efficacy” subsection “3.2.8. Diabetes, Metabolic Syndrome, and Related Disorders.” This was somewhat misleading, as it was grouped with studies such as a 2012 Iranian Effects of broccoli sprout with high sulforaphane concentration on inflammatory markers in type 2 diabetic patients: A randomized double-blind placebo-controlled clinical trial (not freely available).

A commercial perspective pointed out substantial differences between these two studies:

“Where the study described above by Lopez-Chillon et al. investigated healthy overweight people to assess effects of SFN-yielding broccoli sprout homogenate on biomarkers of inflammation, Mirmiran et al. in 2012 had used a SFN-yielding supplement in T2DM patients. Although the data are not directly comparable, the latter study using the powdered supplement resulted in significant lowering of Il-6, hs-CRP, and TNF-α over just 4 weeks.

It is not possible to further compare the two studies due to vastly different time periods over which each was conducted.”


The commercial perspective impressed as more balanced than the clinical trial perspective. The clinical trial perspective also had an undisclosed conflict of interest!

A. The clinical trial perspective:

  • Effectively promoted one commercial product whose supplier was associated with a coauthor;
  • Downgraded several other commercial products; and
  • Tried to shift responsibility for the lack of “minimally effective doses in humans” to commercial products with:

    “Only recently have there been attempts to define minimally effective doses in humans – an outcome made possible by the development of consistently formulated, stable, bioavailable broccoli-derived preparations.”

But unless four years previous is “recently,” using commercial products to excuse slow research progress can be dismissed. A coauthor of the clinical trial perspective was John Hopkins’ lead researcher for a November 2015 Sulforaphane Bioavailability from Glucoraphanin-Rich Broccoli: Control by Active Endogenous Myrosinase, which commended “high quality, commercially available broccoli supplements” per:

“We have now discontinued making BSE [broccoli sprout extract], because there are several high quality, commercially available broccoli supplements on the market.”

The commercial perspective didn’t specifically mention any commercial products.

B. The commercial perspective didn’t address taste, which may be a consumer acceptance problem.

C. The commercial perspective provided practical dosage recommendations, reflecting their consumer orientation. These recommendations didn’t address how much sulforaphane is suitable for healthy people, though.

The clinical trial perspective will eventually have to make practical dosage recommendations after they stop dodging their audience – which includes clinicians trying to apply clinical trial data – with unhelpful statements such as:

“Reporting of administered dose of glucoraphanin and/or sulforaphane is a poor measure of the bioavailable / bioactive dose of sulforaphane.”

How practical was their “internal dose” recommendation for non-researcher readers?


Here’s what I’m doing to answer how much sulforaphane is suitable for healthy people.

I’d like to posthumously credit my high school literature teachers Dorothy Jasiecki and Martin Obrentz for this post’s compare-and-contrast approach. They both required their students to read at least two books monthly, then minimally handwrite a 3-page (single-spaced) paper comparing and contrasting those books.

Each monthly assignment was individualized so that students couldn’t undo the assignment’s purpose – to think for yourself – with parasitical collaboration. This former practice remains a good measure of intentional dumbing-down of young people, the intent of which has become clearer.

You can see from these linked testimonials that their approach was in a bygone era, back when some teachers considered a desired outcome of public education to be that each individual learned to think for themself. My younger brother contributed:

“I can still remember everything Mr. Obrentz ever assigned for me to read. He was the epitome of what a teacher should be.”

Eat broccoli sprouts today!

This 2020 Korean letter to a journal editor cited 23 recent papers in support of sulforaphane’s positive effects, mainly in anti-cancer treatments:

“Gene expression is mediated by chromatin epigenetic changes, including DNA methylation, histone modifications, promoter-enhancer interactions, and non-coding RNA (microRNA and long non-coding RNA)-mediated regulation. Approximately 50% of all tumor suppressor genes are inactivated through epigenetic modifications, rather than by genetic mechanisms, in sporadic cancers. Accumulating evidence suggests that epigenetic modulators are important tools to improve the efficacy of disease prevention strategies.

Because sulforaphane (SFN) induces the nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element pathway that induces the cellular defense against oxidative stress, SFN has received increased attention because it acts as an antioxidant, antimicrobial, anti-inflammatory, and anticancer agent.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7068201/ “A recent overview on sulforaphane as a dietary epigenetic modulator”


Letters to the editor aren’t peer-reviewed, though. One of the cited papers was a 2018 Czech mini-review that included metabolism, preparation and processing evidence:

“Sulforaphane is a phytochemical that occurs in plants in the form of biological inactive precursor glucoraphanin. This precursor belongs to the group of phytochemicals – glucosinolates – that are rapidly converted to isothiocyanate by the enzyme myrosinase.

The process of transformation takes place after a disruption of plant tissues by biting, chewing, slicing, and other destruction of tissues, when myrosinase is released from plant tissues. When myrosinase is destroyed during meal preparation (during cooking, steam cooking, or microwave treatment), a likely source of isothiocyanates is microbial degradation of glucosinolates by intestinal microflora. However, hydrolysis by microflora has been reported to be not very efficient, and in humans it is very diverse and variable.

Content of glucoraphanin in extract from broccoli sprouts was 16.6 μmol per gram of fresh weight. In contrast, mature broccoli extract contained 1.08 μmol per gram of fresh weight. Total amount of glucosinolates in young broccoli sprouts is 22.7 μmol per gram of fresh weight and 3.37 μmol per gram of fresh weight for mature broccoli.

Percentage amount of sulforaphane formed from its precursor glucoraphanin in broccoli which had not been heat treated and had been lyophilized [freeze-dried] was 22.8%. Broccoli steaming (5 min) and its lyophilization decrease the amount of sulforaphane formed to 4.2%.”

https://www.liebertpub.com/doi/full/10.1089/jmf.2018.0024 “Isothiocyanate from Broccoli, Sulforaphane, and Its Properties (not freely available)


Information about 43 completed sulforaphane clinical trials is here. Among them, the 2014 Effect of Broccoli Sprouts on Nasal Response to Live Attenuated Influenza Virus in Smokers: A Randomized, Double-Blind Study was of particular interest, stating:

“Nutritional interventions aimed at boosting antioxidants may be most effective in individuals who are relatively antioxidant-deficient at baseline, a condition likely to be more prevalent in smokers.”

I didn’t notice regular supplement dosage studies. Maybe I didn’t read control group information carefully enough?


https://pubchem.ncbi.nlm.nih.gov/compound/sulforaphane lists sulforaphane’s molecular weight as 177.3 g/mol. A 1 mg sulforaphane capsule weight equals a 5.64 μmol sulforaphane amount (.001 / 177.3).

From the 2015 Sulforaphane Bioavailability from Glucoraphanin-Rich Broccoli: Control by Active Endogenous Myrosinase:

  • Figure 4 showed bioavailability of sulforaphane in a broccoli sprout extract with myrosinase 100 μmol gelcap was 36.1% which weighed 6.4 mg (36.1 / 5.64).
  • Figure 3 showed bioavailability of sulforaphane in freeze-dried broccoli sprouts in pineapple-lime juice was 40.5% in 50, 100, and 200 μmol amounts and 33.8% with 100 μmol gel caps. You do the weight math.
  • Figure 2 showed that if broccoli sprout extract didn’t have the enzyme, bioavailability of sulforaphane was 10.4% whether the amount was 69 or 230 μmol, weighing 1.27 mg (69 x .104) / 5.64 and 4.24 mg (230 x .104) / 5.64.

Bioavailability ranged from Figure 2’s 10.4% to Figure 4’s 36.1%. The question of how much sulforaphane is suitable for healthy people remains unanswered.


Do epigenetic clocks measure causes or effects?

Starting the sixth year of this blog with a 2020 article authored by the founder of the PhenoAge epigenetic clock methodology:

“The Ge[r]oscience paradigm suggests that targeting the aging process could delay or prevent the risk of multiple major age-related diseases. We need clinically valid measures of the underlying biological process and/or classification criteria for what it means to be biologically, rather than chronologically, “aged”.

The majority of aging biomarkers, including the first-generation epigenetic clocks, are developed using cross-sectional data, in which the researchers take a variable that proxies aging (e.g. chronological age) and apply supervised machine learning, or deep learning, approaches to predict that variable using tens to hundreds of thousands of input variables. The problem with this approach is that it doesn’t account for mortality selection. This biases the algorithm to select markers that are not causal, but instead correlative with aging.

When considering individuals of the same chronological age, do those with higher epigenetic age look phenotypically older on average (e.g. have higher mortality rates, greater disease burden, and worse physical and cognitive functioning)? FEV1 [forced expiratory volume in one second] declined at a faster rate for individuals with higher baseline GrimAge and/or PhenoAge. A similar finding was observed for the decline in grip strength as a function of GrimAge; however, the rate of change for any of the epigenetic clocks was not associated with rate of change in any performance measure.

Loci that show consistent trends with chronological age, even at higher ages, are likely not causal. By using a cross-sectional study design for biomarker development there was a propensity away from selecting causal loci, to the point where fewer causal loci were selected than if loci had been chosen at random.

The power of these measures as diagnostic and prognostic may stem from the use of longitudinal data in training them. Rather than continuing to train chronological age predictors using diverse data, it may be more advantageous to retrain some of the existing measures by predicting longitudinal outcomes.”

https://academic.oup.com/biomedgerontology/advance-article-abstract/doi/10.1093/gerona/glaa021/5717592 “Assessment of Epigenetic Clocks as Biomarkers of Aging in Basic and Population Research” (not freely available)


A cited 2019 study modeled corrections to “account for mortality selection.” It modified datasets “by incorporating correlates of mortality identified from longitudinal studies, allowing cross-sectional studies to effectively identify the causal factors of aging.”

https://academic.oup.com/biomedgerontology/advance-article-abstract/doi/10.1093/gerona/glz174/5540066 “Biomarkers for Aging Identified in Cross-sectional Studies Tend to Be Non-causative” (not freely available)


The article didn’t present a complete case to determine whether an individual’s epigenetic clock measurements over time may show causes of biological aging.

Other viewpoints include:

1. A blood plasma aging clock presented evidence with its 46-protein conserved aging signature that some causes of biological aging are under genetic control. If the principle of this finding applies to CpG DNA methylation, the statement:

Loci that show consistent trends with chronological age, even at higher ages, are likely not causal.

may not hold. Such epigenetic changes could be among both the causes of senescence and the effects of evolution’s selection mechanisms.

2. An epigenetic clock review by committee, particularly in:

  • Challenge 3 “Integration of epigenetics into large and diverse longitudinal population studies”;
  • Challenge 5 “Single-cell analysis of aging changes and disease”; and
  • Table 1 “Major biological and analytic issues with epigenetic DNA methylation clocks” with single-cell analysis as the solution to five Significant issues.

Trained immunity responses to bacterial infections

This 2019 Swiss rodent study investigated immune responses to five types of bacterial infections:

“The innate immune system recalls a challenge to adapt to a secondary challenge, a phenomenon called trained immunity. Trained immunity protected mice from a large panel of clinically relevant bacterial pathogens inoculated systematically and locally to induce peritonitis, enteritis and pneumonia.

Induction of trained immunity remodeled bone marrow and blood cellular compartments, providing efficient barriers against bacterial infections. Protection was remarkably broad when considering the pathogens and sites of infection tested.

We are running experiments to delineate the length of protection conferred by trained immunity. Trained immunity is most typically induced with β-glucan.

Mice were injected with methicillin-resistant Staphylococcus aureus (MRSA). Trained mice survived better than control mice (31% vs. 0% survival) and had 10-fold less bacteria in blood 2 days post-infection.

Mice were challenged with a lethal dose of Listeria monocytogenes. Most strikingly, all trained mice survived infection while all control mice died within 5 days. Bacteria were not detected in blood collected from trained mice 2 and 3 days post-infection.”

https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiz692/5691195 “Trained immunity confers broad-spectrum protection against bacterial infections”


One of the coauthors also published:

Clearing out the 2019 queue of interesting papers

I’m clearing out the below queue of 27 studies and reviews I’ve partially read this year but haven’t taken the time to curate. I have a pesky full-time job that demands my presence elsewhere during the day. :-\

Should I add any of these back in? Let’s be ready for the next decade!


Early life

https://link.springer.com/article/10.1007/s12035-018-1328-x “Early Behavioral Alterations and Increased Expression of Endogenous Retroviruses Are Inherited Across Generations in Mice Prenatally Exposed to Valproic Acid” (not freely available)

https://www.sciencedirect.com/science/article/pii/S0166432818309392 “Consolidation of an aversive taste memory requires two rounds of transcriptional and epigenetic regulation in the insular cortex” (not freely available)

https://www.nature.com/articles/s41380-018-0265-4 “Intergenerational transmission of depression: clinical observations and molecular mechanisms” (not freely available)

mother

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6454089/ “Epigenomics and Transcriptomics in the Prediction and Diagnosis of Childhood Asthma: Are We There Yet?”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6628997/ “Placental epigenetic clocks: estimating gestational age using placental DNA methylation levels”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770436/ “Mismatched Prenatal and Postnatal Maternal Depressive Symptoms and Child Behaviours: A Sex-Dependent Role for NR3C1 DNA Methylation in the Wirral Child Health and Development Study”

https://www.sciencedirect.com/science/article/pii/S0889159119306440 “Environmental influences on placental programming and offspring outcomes following maternal immune activation”

https://academic.oup.com/mutage/article-abstract/34/4/315/5581970 “5-Hydroxymethylcytosine in cord blood and associations of DNA methylation with sex in newborns” (not freely available)

https://physoc.onlinelibrary.wiley.com/doi/full/10.1113/JP278270 “Paternal diet impairs F1 and F2 offspring vascular function through sperm and seminal plasma specific mechanisms in mice”

https://onlinelibrary.wiley.com/doi/full/10.1111/nmo.13751 “Sex differences in the epigenetic regulation of chronic visceral pain following unpredictable early life stress” (not freely available)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6811979/ “Genome-wide DNA methylation data from adult brain following prenatal immune activation and dietary intervention”

https://link.springer.com/article/10.1007/s00702-019-02048-2 “miRNAs in depression vulnerability and resilience: novel targets for preventive strategies”


Later life

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6543991/ “Effect of Flywheel Resistance Training on Balance Performance in Older Adults. A Randomized Controlled Trial”

https://www.mdpi.com/2411-5142/4/3/61/htm “Eccentric Overload Flywheel Training in Older Adults”

https://www.nature.com/articles/s41577-019-0151-6 “Epigenetic regulation of the innate immune response to infection” (not freely available)

https://link.springer.com/chapter/10.1007/978-981-13-6123-4_1 “Hair Cell Regeneration” (not freely available)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6422915/ “Histone Modifications as an Intersection Between Diet and Longevity”

https://www.sciencedirect.com/science/article/abs/pii/S0306453019300733 “Serotonin transporter gene methylation predicts long-term cortisol concentrations in hair” (not freely available)

https://www.sciencedirect.com/science/article/abs/pii/S0047637419300338 “Frailty biomarkers in humans and rodents: Current approaches and future advances” (not freely available)

https://onlinelibrary.wiley.com/doi/full/10.1111/pcn.12901 “Neural mechanisms underlying adaptive and maladaptive consequences of stress: Roles of dopaminergic and inflammatory responses”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627480/ “In Search of Panacea—Review of Recent Studies Concerning Nature-Derived Anticancer Agents”

https://www.sciencedirect.com/science/article/abs/pii/S0028390819303363 “Reversal of oxycodone conditioned place preference by oxytocin: Promoting global DNA methylation in the hippocampus” (not freely available)

https://www.futuremedicine.com/doi/10.2217/epi-2019-0102 “Different epigenetic clocks reflect distinct pathophysiological features of multiple sclerosis”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6834159/ “The Beige Adipocyte as a Therapy for Metabolic Diseases”

https://www.sciencedirect.com/science/article/abs/pii/S8756328219304077 “Bone adaptation: safety factors and load predictability in shaping skeletal form” (not freely available)

https://www.nature.com/articles/s41380-019-0549-3 “Successful treatment of post-traumatic stress disorder reverses DNA methylation marks” (not freely available)

https://www.sciencedirect.com/science/article/abs/pii/S0166223619301821 “Editing the Epigenome to Tackle Brain Disorders” (not freely available)

A blood plasma aging clock

This 2019 Stanford human study developed an aging clock using blood plasma proteins:

“We measured 2,925 plasma proteins from 4,331 young adults to nonagenarians [18 – 95] and developed a novel bioinformatics approach which uncovered profound non-linear alterations in the human plasma proteome with age. Waves of changes in the proteome in the fourth, seventh, and eighth decades of life reflected distinct biological pathways, and revealed differential associations with the genome and proteome of age-related diseases and phenotypic traits.

To determine whether the plasma proteome can predict chronological age and serve as a “proteomic clock,” we used 2,858 randomly selected subjects to fine-tune a predictive model that was tested on the remaining 1,473 subjects. We identified a sex-independent plasma proteomic clock consisting of 373 proteins. Subjects that were predicted younger than their chronologic age based on their plasma proteome performed better on cognitive and physical tests.

The 3 age-related crests were comprised of different proteins. Few proteins, such as GDF15, were among the top 10 differentially expressed proteins in each crest, consistent with its strong increase across lifespan. Other proteins, like chordin-like protein 1 (CHRDL1) or pleiotrophin (PTN), were significantly changed only at the last two crests, reflecting their exponential increase with age.

We observed a prominent shift in multiple biological pathways with aging:

  • At young age (34 years), we observed a downregulation of proteins involved in structural pathways such as the extracellular matrix. These changes were reversed in middle and old ages (60 and 78 years, respectively).
  • At age 60, we found a predominant role of hormonal activity, binding functions and blood pathways.
  • At age 78, key processes still included blood pathways but also bone morphogenetic protein signaling, which is involved in numerous cellular functions, including inflammation.

These results suggest that aging is a dynamic, non-linear process characterized by waves of changes in plasma proteins that are reflective of a complex shift in the activity of biological processes.”

https://www.biorxiv.org/content/10.1101/751115v1.full “Undulating changes in human plasma proteome across lifespan are linked to disease”


A non-critical review of the study was published by the Life Extension Advocacy Foundation. Frequent qualifiers like “could,” “may,” and “possible” were consistent with the confirmation biases of their advocacy.

There were several misstatements of what the study did, including the innumerate:

  1. “used around half of the participant data to build a “proteomic clock”
  2. tested it on the other half of the participants
  3. a total of 3000 proteins”

Per the above study quotation, the numbers were actually:

  1. Closer to two thirds (2,858 ÷ 4,331), not “around half”;
  2. The other third (1,473 ÷ 4,331), not “the other half”; and
  3. 2,925 not 3000.

The final paragraph and other parts of the review bordered on woo. Did a review of the findings have to fit LEAF’s perspective?


In contrast, Josh Mitteldorf did his usual excellent job of providing contexts for the study with New Aging Clock based on Proteins in the Blood, emphasizing comparisons with epigenetic clock methodologies:

“For some of the proteins that feature prominently in the clock, we have a good understanding of their metabolic function, and for the most part they vindicate my belief that epigenetic changes are predominantly drivers of senescence rather than protective responses to damage.

Wyss-Coray compared the proteins in the new (human) proteome clock with the proteins that were altered in the (mouse) parabiosis experiments, and found a large overlap [46 proteins change in the same direction and define a conserved aging signature]. This may be the best evidence we have that the proteome changes are predominantly causal factors of senescence.

46 plasma proteins

Almost all the proteins identified as changing rapidly at age 78 are increasing. In contrast, a few of the fastest-changing proteins at age 60 are decreasing (though most are increasing). GDF15 deserves a story of its own.

The implication is that a more accurate clock can be constructed if it incorporates different information at different life stages. None of the Horvath clocks have been derived based on different CpG sites at different ages, and this suggests an opportunity for a potential improvement in accuracy.”

A commentator linked the below study:

https://www.sciencedirect.com/science/article/pii/S0092867419308323 “GDF15 Is an Inflammation-Induced Central Mediator of Tissue Tolerance” (not freely available)

which prompted his response:

“Thanks, Lee! This is just the kind of specific information that I was asking for. It would seem we should construct our clocks without GDF15, which otherwise might loom large.”

An epigenetic clock review by committee

This 2019 worldwide review of epigenetic clocks was a semi-anonymous mishmash of opinions, facts, hypotheses, unwarranted extrapolations, and beliefs. Diversity of viewpoints among the 21 coauthors wasn’t evident.

1. Citations of coauthors’ works seemed excessive, and they apologized for omissions. However:

  • Challenge 5 was titled “Single-cell analysis of aging changes and disease” and
  • Table 1 “Major biological and analytic issues with epigenetic DNA methylation clocks” had single-cell analysis as the Proposed solution to five Significant issues.

Yet studies such as High-Resolution Single-Cell DNA Methylation Measurements Reveal Epigenetically Distinct Hematopoietic Stem Cell Subpopulations were unmentioned.

2. Some coauthors semi-anonymously expressed faith that using current flawed methodologies in the future – only more thoroughly, with newer equipment, etc. – would yield better results. If all 21 coauthors were asked their viewpoints of Proposed solutions to the top three Significant issues of epigenetic clocks, what would they emphasize when quoted?

3. Techniques were praised:

“Given the precision with which DNA methylation clock age can be estimated and evolving measures of biological, phenotype-, and disease-related age (e.g., PhenoAge, GrimAge)..”

Exactly why these techniques have at times produced inexplicable results wasn’t examined, though. Two examples:

  • In Reversal of aging and immunosenescent trends, Levine PhenoAge methodology estimated that the 51-65 year old subjects’ biological ages at the beginning of the study averaged 17.5 years less than their chronological age. Comparing that to Horvath average biological age of 3.95 years less raised the question: exactly why did PhenoAge show such a large difference?
  • The paper mentioned GrimAge methodology findings about “smoking-related changes.” But it didn’t explain why GrimAge methylation findings most closely associated with smoking history also accurately predicted future disease risk with non-smokers.

Eluding explanations for these types of findings didn’t help build confidence in methodologies.

4. A more readable approach to review by committee could have coauthors – in at least one section – answer discussion questions, as Reversing epigenetic T cell exhaustion did with 18 experts.

https://genomebiology.biomedcentral.com/articles/10.1186/s13059-019-1824-y “DNA methylation aging clocks: challenges and recommendations”